Analyses of constituents of oils for lubricating machinery provide information on current conditions of the machinery and may identify problems which may require costly repair if not corrected. Analytical services have been provided through the use of a kit type service in which a sample of engine oil is mailed to an analysis laboratory and a report is furnished after the laboratory conducts an analysis using conventional analysis equipment such as a polychromater with rotatable carbon electrodes. Improved analysis systems and procedures are disclosed in co-pending application Ser. No. 08/191,395, filed Feb. 2, 1994, and entitled "ANALYSIS SYSTEM" the disclosure of which is expressly incorporated herein by reference. While the system and procedures disclosed in that application are suitable for a variety of liquid samples, certain liquid samples such as diesel engine oils, may be of high viscosity, and also may include large amounts of significant constituents such as 2,000 ppm zinc.